U.S. patent number 5,821,405 [Application Number 08/911,213] was granted by the patent office on 1998-10-13 for modular water quality apparatus and method.
This patent grant is currently assigned to Hydrolab Corporation. Invention is credited to Michael Albert Alkier, Terry Lee Dickey.
United States Patent |
5,821,405 |
Dickey , et al. |
October 13, 1998 |
Modular water quality apparatus and method
Abstract
A modular water quality measurement apparatus and method
includes a sealed or unsealed housing with a universal sensor
interface cap (12) and mechanical and electrical sensor connections
(14) for receiving removably attachable sensors (16 or 16'). Each
of the mechanical and electrical sensor connections (14) are
individually electrically connected to a programmable motherboard
(20) within the housing. Sensor daughterboards (22) are removably
attached to the motherboard (20) corresponding to individual
sensors (16 or 16') connected to the universal sensor interface cap
(12). Further, removably attachable input/output daughterboards
(24) are electrically connected to the motherboard (20) for
accommodating various serial interface types and software is
provided for collecting information from the sensors (16 or 16')
and transmitting the information through the input/output
daughterboards (24) for manipulation by a user. Additionally, a
removably attachable plug (26) is provided for sealing mechanical
sensor connections (14) which are not sealed by sensors (16 or
16'). The software includes product software for gathering
information from the sensors (16 or 16'), learnable sensor driver
software for directing the product software and manipulating
gathered information, and learnable interface software for
transmitting the gathered information for further manipulation by
various interface devices. In another preferred embodiment, sensor
(16') while including sensing sensor element (28) as does sensor
(16), further includes a sensor PCB (32) thereby eliminating the
need for sensor daughterboards (22). Sensor (16') is connected to
motherboard (20) by means of sensor interface bus connections (38)
thereby enabling the product to be more compact and efficient.
Inventors: |
Dickey; Terry Lee
(Pflugerville, TX), Alkier; Michael Albert (Austin, TX) |
Assignee: |
Hydrolab Corporation (Austin,
TX)
|
Family
ID: |
24437674 |
Appl.
No.: |
08/911,213 |
Filed: |
August 14, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
608710 |
Feb 29, 1996 |
|
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Current U.S.
Class: |
73/53.01;
73/170.29; 73/431; 73/866.5 |
Current CPC
Class: |
G01D
21/02 (20130101); G01D 18/002 (20130101); G01N
33/1886 (20130101); G01D 11/24 (20130101) |
Current International
Class: |
G01D
11/24 (20060101); G01N 33/18 (20060101); G01D
18/00 (20060101); G01D 21/02 (20060101); G01N
011/00 (); G01G 005/00 (); G01D 011/24 (); G01D
021/00 () |
Field of
Search: |
;73/19.01,53.01,170.29,866.5,431 ;364/509,550 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Williams; Hezron E.
Assistant Examiner: Politzer; Jay L.
Attorney, Agent or Firm: Shaffer, Jr.; J. Nevin Shaffer
& Culbertson
Parent Case Text
This application is a continuation of application Ser. No.
08/608,710, filed Feb. 29, 1996, now abandoned.
Claims
I claim:
1. A modularized sensor apparatus comprising:
(a) a housing with a universal sensor interface cap;
(b) mechanical sensor connections in said universal sensor
interface cap for receiving uniform, removably attachable, sensors,
with each of the mechanical sensor connections individually
connected to a programmable motherboard within said housing;
(c) bi-directional sensor daughterboards removably attached to the
motherboard, corresponding to individual sensors connected to the
universal sensor interface cap; and
(d) software for collecting information from said sensors and
transferring the information for manipulation by a user, said
software comprising product software for gathering information from
the sensor(s), sensor driver software for directing the product
software and manipulating gathered information, and interface
software for communicating with various interface devices and
transmitting the gathered information for further manipulation
wherein:
i. said product software further comprising a product software
services table for said sensor driver software to call comprising
identification services, non-volatile memory write services, and
configuration table read access:
ii. said sensor driver software further comprising a sensor driver
software table comprising sensor driver title and version
identification, parameter number, name(s), and unit(s), parameter
calibration, parameter setup, and parameter data; and
iii. said interface software further comprising the following
functions: identification of product title and software version,
parameter number, name(s), and unit(s) of said product software,
parameter calibration, parameter setup, parameter data, login
status, login setup, and login dump.
2. The apparatus of claim 1, further comprising removably
attachable bi-directional input/output daughterboards connected to
the motherboard for accommodating various serial interface
types.
3. The apparatus of claim 1, further comprising removable,
attachable plugs for sealing sensor connections not sealed by
sensors.
4. The apparatus of claim 1, wherein the uniform, removably
attachable, sensors further comprise:
(a) a sensor sensing element; and
(b) a sealed connector conformed to fit and seal the mechanical
sensor connections in the uniform, sensor interface cap.
5. The apparatus of claim 1, wherein the bidirectional sensor
daughterboards further comprise circuitry, appropriate to specific
sensor type, at the lowest level necessary to operate the
sensor.
6. In a water quality sensing device of the type used to sense
physical and chemical properties of water with sensors, a
modularized sensor apparatus comprising:
(a) a sealed housing with a universal sensor interface cap;
(b) mechanical sensor connections in said universal sensor
interface cap for receiving uniform, removably attachable, sensors
with each of the mechanical sensor connections individually
connected to a programmable motherboard within said housing, the
sensors comprising a sensor sensing element and a sealed connector
conformed to fit and seal the mechanical sensor connections in the
universal sensor interface cap;
(c) bi-directional sensor daughterboards removably attached to the
motherboard corresponding to individual sensors connected to the
universal sensor interface cap;
(d) software for collecting information from said sensors and
transferring the information for manipulation by a user, said
software comprising product software for gathering information from
the sensor(s), sensor driver software for directing the product
software and manipulating gathered information, and interface
software for communicating with various interface devices and
transmitting the gathered information for further manipulation
wherein:
i. said product software further comprising a product software
services table for said sensor driver software to call comprising
identification services non-volatile memory write services and
configuration table read access;
ii. said sensor driver software further a sensor driver software
table comprising sensor driver title and version identification,
parameter number, name(s), and unit(s), parameter calibration,
parameter setup, and parameter data; and
iii. said interface software further comprising the following
functions: identification of product title and software version,
parameter number, name(s), and unit(s) of said product software,
parameter calibration, parameter setup, parameter data, login
status, login setup, and login dump; and
(e) removably attachable plugs for sealing sensor connections not
sealed by sensors.
7. The apparatus of claim 6 further comprising removably attachable
bi-directional input/output daughterboards connected to the
motherboard for accommodating various serial interface types.
8. The apparatus of claim 6, wherein the bi-directional sensor
daughterboards further comprise circuitry, appropriate to the
specific sensor type, at the lowest level necessary to operate the
sensor.
Description
BACKGROUND OF THE INVENTION
This invention relates to a modular water quality measurement
sensor system and in particular to a modularized sensor apparatus
and method.
Both manual and electrical mechanical devices have been known in
the art for quite some time for sensing desired information from
the environment. In particular, as to water monitoring and
measuring devices, an example of prior art electrical mechanical
devices is disclosed in D'Aoust, U.S. Pat. No. 4,662,210, which
utilizes a probe inserted in the water and connected by cable to a
control housing capable of receiving and analyzing a variety of
data from the sensor so as to provide a display of desired
information such as dissolved gas pressure, barometric pressure,
temperature, percent saturation, and difference between total
dissolved gases and barometric pressures. Other types of data have
been deemed needed and sensors have been developed to provide the
data. Certainly, as technology progresses, the ability to sense
other parameters will become practical and other sensors will be
developed. As populations increase and water supplies decrease, the
need for managing water resources becomes more and more critical.
This can only be done when a complete analysis of the quality of
the water being utilized is known.
State of the art water quality products are comprised of four basic
elements. There is a printed circuit board (PCB) containing serial
interface (I/F) circuitry, and I/F circuitry for all compatible
sensors. The serial I/F circuitry is generally an RS232 or SDI-12
serial I/F to a computer, data logger, or other serial device, but
cannot be changed, however, without modifying the PCB. Further, the
sensor I/F circuitry is dedicated to specific functions and cannot
adapt to different sensors without substantial modification. The
second element is PCB-resident software containing the complete set
of measurement control and computational algorithms for all
compatible sensors. The major problem here is that the software
cannot accommodate sensors for which the PCB cannot interface. The
third element is the mechanical connections allowing the sensors to
be attached to the water testing product in dedicated locations.
Most products today constrain sensors to dedicated locations
through mechanical mounting methods. Others limit sensors to
dedicated locations by varying the electrical connector
compatibility. Nonetheless, there are a wide variety of sensors
capable of measuring various water quality parameters that are
available. Currently, if a new sensor is to be added to a product,
the original product has to undergo major modifications, including
wholesale modification of the PCB. As a partial solution, some
products have been designed to allow for the installation and
removal of PCBs which interface to specific sensors.
Drawbacks to the sensors known in the art, however, remain and are
numerous. Today, prior art sensors and sensor products have serial
input/output (I/O) which are a dedicated PCB function which cannot
be replaced without significant PCB rework. Further, serial I/O
data interpretation requires the PC, data logger, or other serial
I/F device to understand the sensor nuances. Modifications and/or
updates to the water quality product may require updates to the
PCB, data logger, or serial I/F to understand these sensor nuances.
Still further, sensors cannot be updated without significant rework
of one or more of the following standard items, that is the PCB,
the sensor mechanical/electrical attachment, and/or the software.
Also, sensors cannot be added to a product without significant
rework of one or more of the following, including the PCB, the
sensor mechanical/electrical attachment, and/or the software. Most
disturbingly, users today must buy functionality which they do not
need and may not want. That is, lower end products contain a full
range PCB and software which has the capability of presenting data
and menu options for features which are not installed on the
product. This situation causes the manufacturer to reduce profits
on minimally equipped products and attempt to recover on fully
equipped products. The end result is the user becomes confused as
to what the product can or cannot do and this confusion costs the
user time and money determining configuration capabilities and
functionalities of the purchased product.
Thus, there is a need in the art for providing a sensor system for
enabling a single product to be compatible with multiple sensors,
multiple interfaces, and multiple sensor circuitry so that a single
product can be easily and economically configured to a user's
requirements and which is capable of enabling upgraded additions of
sensors yet to be desired or developed. It, therefore, is an object
of this invention to provide an improved sensor system for
providing updates and additions of sensors without requiring
significant rework of the PCBs, sensor mechanical/electrical
attachments, or software.
SHORT STATEMENT OF THE INVENTION
Accordingly, the modularized sensor system of the present invention
includes a sealed or unsealed housing with a universal sensor
interface cap. The universal sensor interface cap contains
mechanical sensor connections for receiving uniform, removably
attachable, sensors. Each of the mechanical sensor connections are
individually connected to a remotely-programmable motherboard
within the housing. Additionally, sensor daughterboards are
provided which are removably attachable to the motherboard and
which correspond to individual sensors connected to the universal
sensor interface cap. Removably attachable input/output
daughterboards are connected to the motherboard for accommodating
various serial interface types and software is provided for
collecting information from the sensors and transferring the
information through the input/output daughterboards for
manipulation by a user.
The universal sensor interface cap also includes plugs for sealing
sensor connections not sealed by sensors. The sensors include a
sensing element, known or hereafter developed, and a sealed
connector conformed to fit and seal the mechanical sensor
connections in the universal sensor interface cap.
Another preferred embodiment of the invention includes a uniform
sensor with a PCB, essentially a sensor daughterboard, installed
inside the sensor itself instead of attached to the motherboard. In
this embodiment, the connection to the universal sensor interface
cap is direct, but the attachment of the "sensor daughterboard" to
the motherboard is now through the universal sensor interface
cap.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention
will become more fully apparent from the following detailed
description of the preferred embodiment, the appended claims and
the accompanying drawings in which:
FIG. 1 is a plan view of a preferred embodiment of the modularized
sensor system of the present invention in exploded form without the
sealed housing;
FIG. 2 is a plan view of another preferred embodiment of the
modularized sensor system of the present invention in exploded form
without the sealed housing;
FIG. 3 is a partial section view of the sensor of FIG. 2 showing
the sensor PCB within the sensor itself;
FIG. 4 is a flow chart for product software to daughterboards;
FIG. 5 is a flow chart for product software to sensor driver;
FIG. 6 is a sensor driver memory chart;
FIG. 7 is a product software table structure; and
FIG. 8 is a flow chart for product software to MODBUS.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention are illustrated
by way of example in FIGS. 1-8. With specific reference to FIG. 1,
a modularized sensor 10 includes a sealed housing (not shown) to
which is attached a universal sensor interface cap 12. A plurality
of mechanical sensor connections 14 are provided in universal
sensor interface cap 12. Removably attachable uniform sensors 16
are conformed so as to fit within and to seal mechanical sensor
connections 14. Each of the mechanical sensor connections 14 are
individually connected by sensor connections 18 to a programmable
motherboard 20 conformed to be located within the sealed housing
(not shown).
Also illustrated are sensor daughterboards 22 and input/output
daughterboards 24 designed to be removably attachable to
motherboard 20. Software (not shown and discussed more fully
hereafter) for collecting information from the sensors and
transferring this information through the input/output
daughterboards 24 for manipulation by a user, is also included.
FIG. 1 also shows a removably attachable plug 26 designed to seal
mechanical sensor connection 14 whenever there are more mechanical
sensor connections 14 than there are sensors 16.
Referring now to FIGS. 2 and 3, another preferred embodiment of the
present invention is illustrated. In this embodiment, uniform
removably attachable sensor 16' is a "smart" sensor. That is, it
contains the usual sensor sensing element 28, now known or to be
developed, connected by electrical connections 30, known in the
art, to a sensor PCB 32 connected by electrical connection 34,
known in the art, to sealed connector 36 conformed to just fit
within and seal and make electrical connection with mechanical
sensor connections 14.
Further, in this embodiment, sensor connections 18 are replaced
with sensor interface bus connection 38. Sensor interface bus
connection 38 is connected to motherboard 20. Motherboard 20
includes input/output daughterboards 24. This embodiment also
includes software for collecting information from the sensors and
transferring the information through the input/output
daughterboards 24 for manipulation by a user.
To restate the problem, prior art sensors, including water quality
sensors, require significant rework of the PCBs, sensor
mechanical/electrical attachments, and software whenever sensors
are updated or additions are made. If a sensor changes, the
manufacturer currently must not only redesign the PCB,
mechanical/electrical attachments, and software unique to that
sensor, but the manufacturer must also rework the unchanged
portions of the product because all prior art PCB circuitry is
grouped together, all prior art mechanical/electrical attachments
are unique, and all prior art software measurement and computation
functions are grouped together. Further, updating or adding sensors
to prior art water quality systems may require significant rework
of the software run on the personal computer (PC), data logger, or
other serial interface devices in order to communicate, properly
interpret, and present the sensor information to the user.
The invention solves these problems by providing common interfaces
for the sensor mechanical/electrical attachment, individual PCBs
for sensor circuitry, individual sensor software modules to deal
with the unique sensor interface measurements and computation
algorithms, and "learnable" software interfaces from the individual
sensor driver software modules as well as from the product software
interface to the PC, data logger, and other serial interface
devices. As a result, and as will be more fully described
hereafter, by way of the present invention the manufacturer merely
needs to focus on the effort required to develop the updated or
added sensor, the individual sensor PCB, and the unique sensor
software. The manufacturer, by the present invention, is spared the
burden of reworking the entire product PCB and software and
multiple mechanical/electrical attachments. Further, the
manufacturer and/or user is spared the incompatibility and/or
update burden of reworking software for the PC, data logger, or
other serial interface device due to the "learnable" software
interface.
The four solution elements described above are more particularly
described hereafter. As illustrated in FIGS. 1 and 2, the primary
mechanical attachment problem is solved by this invention by the
universal sensor interface cap 12. The cap 12 provides mechanical
support for the sensors 16 and 16', by mating to threaded collars
(not shown) on sensors 16 and 16'. Any other appropriate mating
method known in the art may also be utilized. Universal sensor
interface cap 12 also physically supports the motherboard 20 by any
means known in the art such as an angle bracket-type configuration
(not shown). Additionally, universal sensor interface cap 12
partially solves the electrical attachment problems of the prior
art, that is, cap 12 contains connectors (not shown) for attachment
to the sensors 16 and 16'. Additionally, as illustrated, sensor
connections 18 and sensor interface bus 38, discussed more fully
hereafter, make the attachment to the motherboard 20.
Motherboard 20 contains input/output connector, power supplies,
microprocessor, non-volatile memory, real-time clock, shared analog
components (analog-to-digital converter, voltage reference, etc.),
and other glue logic necessary to provide a general purpose
measurement and computation platform, as is known in the art. The
motherboard 20 completes the sensor electrical solution to prior
art problems. That is, sensor connections 18 and sensor interface
bus connection 38 provide a method of connecting the sensors 16 and
16' to the motherboard 20. The figures show four sensor connections
18 and sensor interface bus connections 38, but obviously, any
physically practical number may be implemented. Within motherboard
20, traces are routed from the sensor connections 18 to the sensor
daughterboards 22. This wiring method greatly simplifies unique
system configurations in that each sensor connection 18 is routed
to one and only one sensor daughterboard 22 positioned on the
motherboard 20.
The motherboard 20 under the control of the product and sensor
driver software (see FIG. 4), discussed more fully hereafter,
sequences the measurement of each sensor 16 or 16' via interface
signals from the microprocessor to a second connector between the
motherboard 20 and each sensor daughterboard 22. The microprocessor
on the motherboard 20 is digitally interfaced to each sensor
daughterboard 22 via a serial shift register. The microprocessor
clocks the shift register and then loads the shift register output
latches to present digital controls to the sensor daughterboard 22.
The shift register approach allows the sensor daughterboards 22 to
stay "general purpose" since any practical shift register depth is
easily supported. Using these digital shift register outputs, the
microprocessor provides the control signals necessary to properly
excite, sequence, and measure the sensor 16 and 16' outputs. For
example, the microprocessor is able to provide signals to all
sensor daughterboards 22 which enables one and only one sensor
daughterboard 22 to supply its analog signal to the
analog-to-digital converter for digitization. This process can be
accomplished in any way known in the art and as illustrated in FIG.
4.
The input/output connection to a PC, data logger, or other serial
device is provided by motherboard 20 passing connections from an
input/output connector to the input/output daughterboard 24. A
microprocessor, as is known in the art, contained on the
motherboard 20 then interfaces to the input/output daughterboard
24. In this manner, serial input/output is established by the
microprocessor, but the physical electrical interface depends upon
the hardware used by the input/output daughterboard 24.
As a result, the serial interface type can be changed by replacing
input/output daughterboard 24 with one of several styles, such as
RS232, SDI-12, RS422, RS485, or any other preferred interface. The
present invention, by means of input/output daughterboards 24 as
herein described, allows the same base product to connect to newer
equipment without sacrificing compatibility with older established
installations.
In a preferred embodiment, sensor daughterboards 22 connect to the
motherboard 20 in order to complete the sensor connection and to
get control information from the microprocessor. Under
microprocessor control, as explained earlier, the sensor
daughterboard 22 provides an analog voltage or digitized bit stream
representation of the sensor measurement. The circuitry (not shown)
on the sensor daughterboards 22 varies among sensor types, as is
known in the art. The circuitry which is appropriate for a
dissolved oxygen sensor, for example, is not appropriate for a
conductivity sensor. The circuitry on the sensor daughterboard 22,
in this invention, encapsulates the lowest level of unique
circuitry needed to operate the sensor 16 and 16'. Sensor
daughterboards 22 are developed in order to be compatible with
sensors for determining conductivity, dissolved oxygen, pH, redox,
ammonium, nitrate, turbidity, and isolated analog voltage inputs,
as well as any other desired input developed now or hereafter.
The sensors, 16 and 16', are comprised of a sensor sensing element
28 attached to a sealed connector 36 with a threaded collar (not
shown). The sensor sensing elements 28 are no different than the
sensing elements known in the art or hereafter developed. The
sealed connectors 36 are conformed so as to provide the common
mechanical and electrical interface disclosed in the invention.
That is, all sensors 16 and 16' are uniform and share a common
connector and the same threaded collar, for example, but the
sensing elements 28 can be as varied as the types of measurements
to be made.
Referring now to FIGS. 4-8, the present invention requires software
for collecting information from the sensors 16 and 16' and
transferring the information through the input/output
daughterboards 24 for manipulation by a user on PCs and so forth.
Any suitable software that accomplishes that is appropriate.
Nonetheless, discussion of the type of software is provided for a
full understanding of the invention. In general, the software
utilized by the invention includes three types, "learnable" sensor
driver software, product software, and "learnable" interface
software. Sensor driver software contains the algorithms needed to
measure the sensor 16 and 16' by controlling the sensor
daughterboard 22. Because further processing is generally required
for all sensors 16 and 16', these computation algorithms are
encapsulated within the sensor driver software. The product
software is the software on the motherboard 20 which provides
software services such as I/O, multiply, divide, etc., as is known
in the art. Further, the product software contains a configuration
table in non-volatile memory which points to the location of
installed sensor drivers (see FIG. 5). Initially, the configuration
section is empty as no sensors 16 or 16', daughterboards 22, or
sensor driver software have been installed. After determining the
product configuration, a user will install the appropriate sensors
16 and 16' into the universal sensor interface cap 12, install the
appropriate sensor daughterboard 22 into an available motherboard
20 location, and install the selected input/output daughterboard
24. At that point, the product must then be attached to a device to
download the sensor drivers for the selected sensors 16 and 16'.
This process is most easily done by a PC using an XMODEM type of
protocol, but any download operation could be used. The product
software saves the sensor driver into an unused location within the
non-volatile memory on the motherboard 20 and updates the
configuration table.
A primary requirement for the sensor driver is that it be
"learnable." That is, the product software need not know any unique
capability of the sensors 16 or 16', but must be able to gather all
information necessary to gather data from the sensors 16 or 16',
display data to the user, execute sensor setup, and execute sensor
calibration. For this embodiment, parameter passing may follow any
conventional software protocol, pointer to global, stack reference,
register based, etc., but the beginning of each sensor driver must
contain a table which contains pointers to the following
functions:
Identification: The sensor driver must state the sensor driver
title and version.
Parameter number, name(s). and unit(s): The sensor driver must
report the number of parameters which can be produced by the sensor
16 or 16' as well as the parameter names and units. The sensor 16
or 16' attached to the sensor daughterboard 22 may produce multiple
values which the product software must understand. For example, a
conductivity sensor is only one sensor, but conductivity, specific
conductance, salinity, and total dissolved solids are parameters
which may be computed from this one sensor. Additional values
supplied by this function include display format, minimum in range
value, maximum in range value, suitability as an X-axis value on an
X-Y graph, and calibration capability and range.
Parameter calibration: After learning the calibration capability,
the product software, under user direction, must call the sensor
driver calibration function for the specified parameter. The sensor
driver will compute new calibration constant(s) for the given
parameter.
Parameter setup: Sensors 16 or 16' may require specific setup
information be available. The product software will call this
function, under user direction, to gather questions to ask the
user. After the user completes the questions, the sensor driver
will adjust the setup information which will be applied to the next
setup request and data request.
Parameter data: After learning the parameter types, the product
software may request data from any parameter supplied by the sensor
driver. The product software will pass an index within the range 0
to number of parameters minus one to specify which data value is
desired. The sensor driver described above can be established by
any means and methods known in the art and as illustrated in FIG.
6.
In order to execute the above functions, the sensor driver requires
access to certain product software capabilities. Granting access to
these capabilities within the product software helps maintain small
sensor drivers as well as preventing updates to the motherboard 20
and product software from requiring updates to the sensor drivers.
For this embodiment, the product software provides a fixed location
table in memory to pointers to product software services for the
sensor driver to call. The following services, at a minimum, are
required:
Identification: The product software must state its driver
interface version. This allows the sensor driver to downgrade
capability if necessary to be compatible with possibly older and
obsolete product software driver interface versions.
Math functions: The location of the floating point add, subtract,
multiply, divide, polynomial functions, etc. must be specified.
Non-volatile memory erase/write: The sensor driver must be capable
of maintaining its calibration constants.
Configuration table read access: The sensor driver may require data
from another sensor. For example, specific conductance requires
temperature data for temperature compensation. The conductivity
sensor driver, when asked to produce specific conductance, must be
able to locate and call the temperature sensor driver in order to
complete its computation.
The product software table structure can be that of any known in
the art and as illustrated in FIG. 7.
The "learnable" interface describes the communication between the
motherboard 20 and a PC, data logger, or the like, not shown and
known in the art. Just as in the sensor drivers, the present
invention allows a user to attach products equipped with different
sensor configurations to a PC, for example, which allows the PC to
gather all information necessary to collect data from the product,
display data to the user, execute sensor 16 or 16' setup, and
execute sensor 16 or 16' calibration.
For this embodiment, the product executes a MODBUS protocol (see
FIG. 8), but any similar protocol may be utilized, with several
custom user defined functions. MODBUS is chosen due to a
well-defined timing and structure, but the user-defined functions
are necessary to deal with the differences between programmable
logic controllers and water quality instruments. MODBUS is a
master/slave protocol. The PC acts as a master while the product
operates as a slave. Because the interface software must be
learnable, the following functions are required for
"learnability":
Identification: The product must state its title and product
software version.
Parameter number name(s), and unit(s): The product software must
report the number of parameters which can be produced by all the
installed sensors 16 and 16' as well as the parameter names and
units. This output is essentially a compilation of the installed
sensor driver outputs. The data is passed through to the PC.
Additional values supplied by this function include display format,
minimum in range value, maximum in range value, suitability as an
X-axis value on an X-Y graph, and calibration capability and
range.
Parameter calibration: After learning the calibration capability,
the PC software, under user direction, must call the product
software calibration function for the specified parameter. The
product software via the sensor driver will compute new calibration
constant(s) for the given parameter.
Parameter setup: Sensors 16 or 16' may require specific setup
information be available. The PC will call this function, under
user direction, to gather questions to ask the user. After the user
answers the questions, the product software via the sensor driver
will adjust the setup information which will be applied to the next
setup and data request.
Parameter data: After learning the parameter types, the PC may
request data from any parameter supplied by the product software
via sensor drivers. The PC will pass an index within the range 0 to
number of parameters minus one to specify which data value is
desired. The product software will translate this index into the
appropriate sensor driver and index to specify which data value is
desired.
Logging status: The product may have logging capability which can
be accessed via the PC. The product returns a table containing, at
a minimum, the log file name, setup date, start date, stop date,
interval, and size. In addition, this function returns the amount
of memory and battery capacity remaining as well as the expected
run out given current usage.
Logging setup: The PC can specify a new logging operation to
execute or modify an existing setup.
Logging dump: The PC can specify a logging file to dump. This dump
can be based on the entire file or by specifying a start/stop date.
All other MODBUS transactions can be executed within a single
MODBUS master/slave transaction. This dump function, due to the
volume of data, is broken into discrete blocks. The PC requests a
block and the product responds with that block. After manipulating
this block, the PC may request a retransmission or request the next
block. This process continues until the product returns a "no more
data" block or the PC aborts the dump.
As illustrated in FIGS. 2 and 3, another preferred embodiment of
the present invention is illustrated. In this embodiment, universal
sensor interface cap 12 still has common connectors 14, but now the
wires are tied together in a common sensor interface bus 38
arrangement. This bus 38 arrangement is analogous to the
microprocessor connections to sensor daughterboards 20 of the first
embodiment. The universal sensor interface cap 12 and sensor
interface bus 38 solves the common mechanical/electrical attachment
requirement. In this embodiment, as compared to the first, the
motherboard 20 loses the multiple sensor daughterboards 22 and
locations and the sensor connections 18 to be replaced by a single
sensor interface bus 38 connection. All other attributes about the
motherboard as previously described remain unchanged.
The sensor PCB 32, in this embodiment, is essentially a sensor
daughterboard which is installed inside the "smart" sensor 16'
instead of being attached to the motherboard 20. The connection to
the sensing element 28 is now direct, but the attachment to the
motherboard 20 is now through the universal sensor interface cap 12
and the sensor interface bus connections 38. All other attributes
of the sensor daughterboards 22, as previously described, are
shared with the sensor PCB 32.
The sensor sensing element 28 is similar to the sensors 16 except
that direct connection to the sensor board is within the sensor 16'
and not distributed through universal sensor interface cap 12 and
motherboard 20 to a daughterboard 22. Otherwise, the sensing
elements 28 are no different than sensing elements 28 described in
the prior embodiment. Likewise, the product software, sensor
driver, and learnable interface are identical to that described
above.
As can be appreciated from the above description, a method of
modularized sensing includes providing a sealed housing with a
universal sensor interface cap 12. The housing can be unsealed, as
well, and is any type known in the art for containing and/or
supporting the subject components. The universal sensor interface
cap 12 is provided with mechanical sensor connections 18 for
receiving removably attachable sensors 16. The mechanical sensor
connections are individually connected to a programmable
motherboard 20 within the housing. Likewise, removably attachable
sensor daughterboards 22, corresponding to individual sensors 16
connected to the universal sensor interface cap 12, are attached to
the motherboard 20. Further, removably attachable input/output
daughterboards 24 are attached to the motherboard 12 for
accommodating various serial interface types. Next, software is
provided for collecting information from the sensor 16 or 16' and
transmitting the information through the input/output
daughterboards 24 for manipulation by a user. The user determines
the desired product configuration of the sensor apparatus, installs
the appropriate sensors 16 or 16' into the universal sensor
interface cap 12, installs the appropriate sensor daughterboard 22
into an available motherboard 20 location, and installs the
appropriate input/output daughterboard 24. Next, the sealed housing
is attached to an interface device for downloading sensor driver
software for the selected sensors 16 or 16' and the sensor driver
software is saved, by means of product software, within the memory
on the motherboard 20. At this point, the user operates the sensor,
the data is collected within the product, and the gathered
information is transmitted through the input/output daughterboards
24 for manipulation by the user. The method also includes using a
removably attachable plug 26 for sealing sensor connections 14 not
sealed by sensors 16 or 16'.
The above described preferred embodiments are intended to
illustrate the principles of the invention, but not to limit the
scope of the invention. For example, while the particular invention
is directed to modular water quality measurement sensor systems, it
applies equally as well to other sensor apparatus and methods as
well. Further, various other embodiments and modifications to these
preferred embodiments may be made by those skilled in the art
without departing from the scope of the following claims.
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